1. Field of the invention
The present invention concerns a device for controlling the circulation of gases from and towards an internal combustion engine chamber, in particular a reciprocating or rotary two stroke or four stroke engine, comprising a throttle or rotor comprising grooves or a lateral notch defining the respective transverse exhaust or intake passages. In combustion engines fitted with this type of distribution, the throttle carries out a continuous revolving movement synchronized with the rotation of the engine around an axis parallel to the axis of rotation of the engine in order to carry out successive phases of the engine cycle by connecting to the exhaust, and where necessary, to the intake, a passage directly connected to the combustion chamber.
2. Description of the Prior art
According to a known embodiment of this type of engine (French patent applications Nos. 83 12071 and 82 12072) for operation at high speeds of rotation, the throttle is contained within a transverse bore into which emerges an orifice directly connected to the combustion chamber, with the intake and/or outlet orifices respectively connected to an exhaust collector. The passage connected to the combustion chamber is provided with a sealing ring housed in a bore and pushed on the throttle by a continuous sealing surface around the orifice directly connected to the combustion chamber under the application of the pressure prevailing in the combustion chamber, and surrounded by one or several sealing elements such as piston rings, this sealing ring being able to slide within the bore and its stroke being limited, on the one hand, by the throttle, and, on the other hand, by a retaining shoulder.
Such combustion engines appear adapted to deliver much higher power to weight ratios than known and tested solutions, in particular for small cubic capacity engines, due to the absence of distribution pieces subjected to a reciprocating movement causing a pulsation limit frequency. The most important advantage of this type of distribution lies in the possibility of having exhaust and intake pipes whose diameter is twice as great as a standard valve system, thus allowing to obtain an improved air filling and thus a much higher specific power.
After a thorough initial testing of the rotary throttle distribution devices, it appeared that these distribution rotor systems presented operating drawbacks or defects that did not enable the advantages mentioned herein-above to be fully worked.
Among these various drawbacks should be cited the difficulties of ensuring the lubrication and the cooling of the sealing elements, which causes excessive wear of the throttle and of the sealing elements and members, high oil consumption, and which can lead, in certain limit cases, to the seizing of the throttle within its bore.
Furthermore, when the distribution by rotary throttle is applied to four stroke engines, no decrease of the specific motor-fuel consumption is observed with respect to engines operating according to a two stroke cycle. This over-consumption of motor-fuel is apparently due to an insufficient separation of the pipes or of the intake and exhaust phases which provoke:
a dilution of the fresh gases by the exhaust gases which is shown by the poor combustion and increased pollution;
an introduction of the vaporized fuel in the exhaust gases also causing an increase in both pollution and the motor-fuel specific consumption.